Expandible work holder



1946. BENJAMIN EXPANDIBLE WORK HOLDER Filed Aug. 25, 1944 INVENTOR [0u/3BENJAM/N ATTbRNEY Patented Jan. 8, 1946 UNITED STATES PATENT OFFICE EXPANDIBLE WORK HOLDER "Louis Benjamin, Brooklyn, N. Y. Application August 23, 1944, Serial No. 550,834 1 2.01aims. o|.2r9.-2)

This invention is an expandible work holder and more particularly is concerned with improved and serviceable means for desirably sustaining wooden objects during fashioning thereof or carving thereon suitable designs. One object of the invention is realized in the provision of a work holder of the character referred to wherein the work is appropriately and securely held on the holder against slippage during the process of carving. Another object of the invention resides in the provision of eflicient and conveniently adjustable means for efiectively but detachably gripping the work to bodily rotate with the holder and against slippage relative thereto. A further object is to provide a chuck having novel means in the form of a slidably guided plunger for actuating spheroidal wedgeable means for outwardly directing serrated swingable gripping fingers against a workpiece removably mounted thereon to clamp the workpiece against displacement relative to the chuck. As a further object the invention contemplates the provision of appropriately accessible and rotary means for actuating a linearly guided member to operate the plunger or tumbler to control the displacement of the braking or wedging spheroidal member. Further objects, features and functional and structural advantages of the invention will appear from the following detailed description taken with the accompanying drawing wherein:

Fig. 1 is a side view of the work holder according to the preferred embodiment of my invention.

Fig. 2 is a longitudinally sectional view on the line 22 of Fig. 1.

Figs. 3 and 4 are transverse sectional views on the lines 3-3 and 4-4 of Fig. 2, and

Fig. 5 is a front view of the work holder however with chuck thereof removed to illustrate the rectilinearly guided driving pin controlled by the outside rotatable collar or driving means.

Illustrative of the embodiment disclosed, the work or workpiece W is removably clamped by the holder generally designated H which comprises. a chuck C removably mounted on the spindle S, control or regulating means in the form of a rotatable collar It adjustably surrounding the spindle, driven means D disposed dia- V metrically of and within the regulatory means R, rectilinearly guided plunger or tumbler means P slidably guided by the externally threaded nipple N of the chuck, and the braking or wedging spheroidal member or ball B for swingably and outwardly displacing the hinged fingers F attached to the chuck.

More particularly, however, the hollow spindle S embodies the annular stop or flange ill to limit the rotational ,displacementof the regulator R on the spindle S in a direction away from the chuck C. This regulator is provided with an internally threaded bore ll adjustably interlocked with the external threads l2 of the hollow stem 7 or socket l3 integral with the spindle S. The

socket I3 is also internally threaded to characterize the teeth l4 removably cooperating with the externally arranged teeth 15 of the nipple N of the chuck C.

Interrupting the internally and externally threaded socket i3 is an opening l6 and a diametrically opposed gap H which is substantially coextensive with the length of the socket as illustrated. v This gap and openin position the driven pin D diametrically of the enlarged bore l3 of the cylindrical regulator R which has an annular abutment shoulder [9 for cooperating'with the ends of the driven pin D to shift thelatter in a linear direction but relative to the nipple upon rotation of the regulator or control means R in respect to the spindle S. V U

Where the driven pin D is rectilinearly displaced relative to the socket l3 upon rotation of the regulator, the slidably guided tumbler or plunger P is correspondingly displaced and in a direction towards or against the freely mounted ball or wedge B. Hence the latter is actuated or driven in a direction away from the internally and externally threaded extension l3.

It should be observed that the companion and hinged fingers F include cooperative biased and inclined faces 20. If therefore the plunger P is slidably directed towards the ball 13, the latter drives against the internal and inclined faces 20, thus causing fingers F to pivot on their fulcrum pins 2| appropriately held in the body of the chuck C. O in other words if the regulator be operated, the driven pin D shifts the slidable plunger to drive the ball against the inclined or cam faces 2|, thus swingably shifting the gripping fingers outwardly or against the work W mounted in the chuck. In effect the ball causes the externally serrated portions 22 of these fingers to firmly wedge against the work. By such action, the work W is positively gripped and bodily rotates with the chuck C as the latter rotates with the spindle removably sustained in appropriate rotatable means 23.

I To remove the work W from the chuck C, the regulator is first rotated in a direction to disengage the abutment annular shoulder l9 from the ends of the driven pin D. Hence the pressure tion from the workpiece W and the latter may be removed from the chuck. I 7

When. the chuck is in a contracted or closed relation the fingers i are retracted as illustrated in Fig. 3 so that their apices of the inner beveled faces which define the teeth T are close toe However when the regulator R is actuether. 7 ated the wedge B may be readily adjusted :toithe spindle having a socket including an internally threaded bore for adjustably receiving said nipple and including externally arranged threads and including diametrically arranged slots, a ball within said chuck for engagement with said inclined surfaces, plunger'means'concentrically and slidably disposed Within said nipple and in part projecting into said chuck for engaging said ball,

pin means disposed normal to said plunger means and slidably guided in saidslots forract iating said plunger means, and an jiinternallythreaded rotatable and adjustable member coacting with said -externally arranged threads and having means desired pressure required to'hold theswingable fingers clamped against the workpiece to "preclude the latter .from involuntary slippage ;;rela'.

regulator, suitable wings or arm 26 are attached thereto. v 1 a I ln themattersof assembly, the regulator is first m unted on the threaded extension or .socket J3 Thereafter the-pinD is threaded into iopening i6 and dropped into-gap H. I .Subseguentl -..the wed eB .is'dropped into the opening 25, the slidable plungernis inserted into the bore .24 .of the nipple to partly ;;project into the topening 25 defined by the Zswingable f ngers and to -partly project or overhang the nip-pie.

Pursuant thereto, the -nipplerN is threaded into the socket l3. Now by rotating thercgulatorthe' coacting with said pin means to drive the latter :against said plunger means whereby the latter idrivessaid ball against said surfaces for spreading and removably clamping said fingers against gysaidworkpiece. tive to the chuck. To facilitate rotation oi the I 2. A holder'for removably 'sustaining 'a work piece, comprisinga hollow chuck having an exteriolz y ;6hreade;d and reduced nipple, serrated fingers fhaving corresponding ends 'pivotedto and intermediate :of said :chuck and havin internally disposed inclined and rectilinear surfaces diverging in =;a direction towards said :nipple, axhollow spindle having :at :one end .3. sooketincluding an internally threadedibore for adjustablyreceivmgsaidnipple-and;includingexternally arranged threads -:and including diametrically arranged s1ots, .a-ba11 withinsaidchuck for engagementfwith said surfaces, gplunger means; concentrically land slidahly guided. within -saidi;nil ple and in 'part projecting into :said .chuck for engaging :said;ba11, pingmeans disposed normal tosaidplunger means and sslidably guided in said slots iforiactuatin said plunger :means and having terminals extending ioeyondsaid nipple, .and aninternal-ly thread ed rotatableand-adjustableimember coacting with said :extemally arranged threads and having an 3 9 annular shoulder coacting with said terminals to drivesthepin gagainstsaid plungermeans whereby the latter drives :saidball against said surfaces fingers against said workpiece.

Louis BENJAMINi 

